The discontent was soon allayed by a successful dash upon Brentford. The town was taken, though not without hard fighting, and there was captured also a good supply of guns and ammunition. The question as to whether this advance, pending negotiation, was or was not a breach of faith on the King's part has been much debated. No cessation of arms had been agreed on, but the Parliament, thinking it a mere oversight, had sent again in order to arrange it. At the same time Essex was warned to hold all his forces ready for battle, but to abstain from acts of hostility. Essex having advanced towards him, the King would have been completely surrounded, had he not seized upon Brentford. Therefore, from the military point of view, the advance was altogether justifiable; from the political, it was unwise, for it lost Charles the hearts of the Londoners. "Charles's error," says Professor Gardiner, "lay in forgetting that he was more than a victorious General."[37] The King's triumph was short-lived. The citizens and the Parliamentary troops rallied to the defence of the capital. An army, twice as large as that of Charles, barred his way on Turnham Green. Essex advancing on Brentford, forced Rupert to retire. This he did in excellent order, entrusting the conduct of the retreat to Sir Jacob Astley. The Prince himself stood his horse in the river beside the bridge that he might watch his men pass over. And there he remained for hours, exposed to a heavy fire, and all the while "cheering and encouraging the retiring ranks to keep order, and to fire steadily on the advancing foe."[38] His troops passed that night drawn up on Hounslow Heath; {100} thence Rupert conducted them to Abingdon, himself returning, November 22nd, to the King at Reading.